Combination treatment with PI3K/mTORC inhibitors and ATRA decreases cell viability in AML cells. MV4-11 cells were treated as indicated with combinations of BEZ (1µM), WYE (1µM) or ZSTK (2.5µM) and ATRA (0.1 µM). Number of cells was determined by CellTiter-Glo¨ luminescent cell viability assay (Promega). Data were analyzed by one-way ANOVA (P < 0.0001) followed by TukeyÕs post-hoc test. * P< 0.05, ** P < 0.01, *** P < 0.001,**** P < 0.0001.